org.jboss.dna.graph.query.process
Class ProcessingComponent

java.lang.Object
  org.jboss.dna.graph.query.process.ProcessingComponent

Direct Known Subclasses:

AbstractAccessComponent, DelegatingComponent, JoinComponent, NoResultsComponent, SetOperationComponent

@NotThreadSafe
public abstract class ProcessingComponent
extends Object

A component that performs (some) portion of the query processing by returning the tuples that result from this stage of processing. Processing components are designed to be assembled into a processing structure, with a single component at the top that returns the results of a query.

Method Summary

void	close() Close these results, allowing any resources to be released.
abstract List<Object[]>	execute() Execute this stage of processing and return the resulting tuples that each conform to the columns.
QueryResults.Columns	getColumns() Get the column definitions.
QueryContext	getContext() Get the context in which this query is being executed.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getContext

public final QueryContext getContext()

Get the context in which this query is being executed.

Returns:

context

getColumns

public final QueryResults.Columns getColumns()

Get the column definitions.

Returns:

the column mappings; never null

execute

public abstract List<Object[]> execute()

Execute this stage of processing and return the resulting tuples that each conform to the columns.

Returns:

the list of tuples, where each tuple corresonds to the columns; never null

close

public void close()

Close these results, allowing any resources to be released.